A color picture tube includes an electron gun for forming and directing three electron beams to a screen of the tube. The screen is located on the inner surface of the face plate of the tube and comprises an array of elements of three different color emitting phosphors. A shadow mask, which may be either a formed aperture or a grill type mask, is interposed between the gun and the screen to permit each electron beam to strike only the phosphor elements associated with that beam.
The shadow mask is subject to vibration from external sources (e.g., speakers near the tube). Such vibration varies the positioning of the apertures through which the electron beam passes, resulting in visible display fluctuations. Ideally, these vibrations need to be eliminated or, at least, mitigated to produce a commercially viable television picture tube.